3 recent biggest upsets in a grand slam final

#1- US Open 2009 final – Juan Martín del Potro def. Roger Federer 3–6, 7–6(7–5), 4–6, 7–6(7–4), 6–2

Federer should have buried this match in straight sets

Federer was the number one seed and defeated Robin Söderling in four sets in the quarter-final and Novak Djokovic in straight sets in the semi-final. Del Potro was seeded sixth and defeated Marin Čilić in four sets in the quarter-final and Rafael Nadal in straight sets in the semi-final.

Federer was unstoppable in the first set. He broke Del Potro in the second game of the first set with an amazing inside-in forehand winner and consolidated by holding his serve to take a 3-0 lead. Federer would go on to win the opening set 6-3.

In the second set, Del Potro double-faulted on break point to allow Federer to get the break of serve in the opening game. The set then remained on serve until Federer served for the set at 5-4. It was 30-30 and Del Potro’s chance to win US open was on a knife-edge as Federer was just two points away from a two-set lead. At 30-30, Del Potro was too far behind the baseline, and with Federer approaching the net, Del Potro hit an inside-out forehand winner that was called out by the umpire.

But, it was at this stage, that technology would prove to be a knight in shining armour for Del Potro, as he was quick to challenge the call and the replay showed that the ball had just barely caressed the line and all of sudden Del Potro had a break point and he broke Federer's serve to make it 5-5 with carbon copy of the same shot, but this time the ball was well inside the line. Federer’s approach to venture the net was badly misfiring as it enabled Del Potro to take risky chances that paid off. Del Potro would go to win the second set 7-6(7-5) in a tie-breaker.

Del Potro started to find his rhythm in the latter half of the second set

In the third set, both players exchanged break of serves in the seventh and eighth game of the set. However, Del Potro continued to punish Federer when he approached the net with some astonishing winners. Del Potro was serving at 4-5 (30-40) in the third set, which meant that Federer had a set point on Del Potro ‘s serve. Unnerved by the situation Del Potro double-faulted to lose and gift Federer the third set.

In the fourth set, Federer had two break points early on at 1-0 in the fourth set. It looked like Del Potro was starring down the barrel, but it was this juncture Del Potro handled the situation with remarkable sang-froid. With his impressive dexterity, he saved both the breakpoints with two consecutive forehand winners. Del Potro saved another break-point at 2-1 with a forehand passing shot. At 2-2, Del Potro had three-point break-points with a chance to get a critical break of serve in the fourth set and he did after Federer sent his forehand wide. But, Federer would break Del Potro back in the eighth game to make 4-4, and the set went to a tie-breaker. Del Potro took control of the tie-break and rose to a 3-0 lead. He had 2 set points at 6-4 when Federer uncharacteristically sent his forehand too long which made it two sets all.

Can Del Potro take inspiration from 2009 final and upset another big name come Sunday at the US Open final?

In the fifth set, Del Potro led 1-0 and had a break point at 30-40. Federer committed the same cardinal sin of approaching the net prematurely and Del Potro made him pay dearly by firing a forehand winner and got an important break of serve to lead 2-0. After that, Federer was in a state of consternation and couldn’t seem to find a way to get back in the match. Del Potro had a championship point at 5-2 and converted it after Federer sent his backhand long behind the baseline. Del Potro couldn’t control his emotions as he won his first grand slam at age of twenty and in the process is the only player outside top 5 in history to beat both Federer and Nadal in the same grand slam.

But, in the overall scheme of things, this was one match Federer should have won in straight or four sets, had he just been a little more cautious with his approach and tactics at critical junctures in the match, especially when he was serving for the second set at 5-4 and when he had multiple break point opportunities in the fourth set. And Federer’s inveterate unforced errors too didn’t help his cause.